Explosively actuated fastener driving tool



Feb., Y, 1967 TGSHISHIGE SEKIGUCMH 5TM. 3,392,849

EXPLOSIVELY ACTUATED FASTENER DRIVING TOOL 4 Shes-Sheet l Filed April 2e, 1965 Mbs i967 TQSHESHIGE sEmGUcHl ETAL EXPLDSIVELY ACTUATED FASTENER DRIVING TOOL Filed April 26, 1965 4 SheeJs-Sheet 2 Wega. 7, 1967 TGSIHHSl-HGE SElKlGUGH TAL EXPLOSVELY ACTUATED FASTENER DRIVING TOOL Filed April 26, 1965 4 Sheets-Sneek :E

mams-micas: sEKnGucH ETAL 3,30%@

EXPLOSIVELY ACTUATED FASTENER DRIVING TOOL 4 Sheets-Sheet 4 Feb 7, i967 Filed April 26, 1965 i, m.n

United States Patent O 3,302,840 EXPLOSIVELY ACTUATED FASTENER DRIVING TOOL Toshishige Sekiguchi, Tokyo, and Meikichi Saba, Sagamihara, Japan, assignors to Japan Drive-It Co., Ltd., Tokyo, Japan Filed Apr. 26, 1965, Ser. No. 450,758 Claims priority, application Japan, Apr. 27, 1964, S19/23,747 7 Claims. (Cl. 227-8) j This invention relates to an explosively actuated power tool for driving fasteners such as studs, pins or the like into a wall such as of wood, steel, concrete or the like, and more particularly relates to improvements in an explosively actuated fastener driving tool of the type having a driving piston or plunger.

Various kinds of explosively actuated fastener driving tools of the type wherein the combustion gases of a cartridge cause an intermediate piston to be propelled and strike the fastener in the tool barrel to drive the same into the wall toward which the tool is directed are well known in the art.

However, conventional tools of this type have various drawbacks. For example, it is necessary to use cartridges having different explosive powers depending on the hardness of the wall into which the fastener is to be driven and also on the desired fastener penetration depth. Furthermore, it has been conventional for the operator to have a plurality of pistons having different lengths and to select a proper one from among them depending upon the particular length of the fastener.

In order to facilitate the speedy operation of the tools of this general type, it is necessary to make it easy to charge a cartridge into a cartridge chamber and to eject the used cartridge out of said chamber. Various proposals have been made to enable automatic ejection of the used or waste cartridge after the driving operation. However, the mechanisms are complicated and occupy a relatively large space.

Still another disadvantage of conventional fastener driving tools of the general type described is in that when the fastener (and hence, the plunger or piston) is excessively driven for some reasons such as excessive explosive power, or unexpected softness of the wall into which the fastener has been driven, causes a strong shock which adversely affects the tool.

It is well known that the general mechanism of fastener driving tools of this kind is similarto the usual pistol or gun operated with a ball-cartridge so that there is a danger that the tool (which should be solely for construction) is abused by being used with a ball-cartridge instead of a blank-cartridge.

It is well known that the interior of the driving tool, particularly the barrel is contaminated with the combustion products of the cartridge. The combustion products are corrosive and their accumulation adversely affects the smooth operation of the tool. Therefore, it is desired to prevent the accumulation of the combustion products and keep the barrel clean' at alltimes.

Therefore, it is an object of this invention to provide an explosively actuated fastener driving tool of the pistontype which is easily adjustable to vary the explosive power even with a standard cartridge having a predetermined explosive power.

It is another object of this invention to provide an explosively actuated fastener driving tool of the pistontype which is easily adjustable to be adapted to various lengths of the fastener.

It is another object of this invention to provide an explosively actuated fastener driving tool of the pistontype wherein the used or waste cartridge can be automatically ejected by means of a very compact and simple ejecting mechanism.

ice

It is still another object of this invention to provide an explosively actuated fastener driving tool of the pistontype wherein means is provided to prevent an undue shock from being transmitted to the tool.

Another object of this invention is to provide an explosively actuated fastener driving tool of the pistontype which is so constructed as not to be abused by being used with a ball-cartridge.

Still another object of this invention is to provide an explosively actuated fastener driving tool wherein the barrel is automatically cleaned to remove the combustion products of the tired cartridge at each driving operation.

Other objects of this invention. will be clear from the following detailed explanation made with reference to the accompanying drawings in which:

FIG. 1 is a side elevation in longitudinal section of a fastener driving tool embodying this invention, with the barrel in the fully extended position;

FIG. 2 is a view similar to FIG. l but with the barrel in a slightly retracted position;

FIG. 3 is a plan view of FIG. Il;

FIG. 4 is an enlarged plan View of the barrel member;

FIG. 5 is a cross-section taken along line A--A of FIG. 1;

FIG. 6 is a cross-section taken along line B-B of FIG. 1;

FIG. 7 is a cross-section taken along line C-C of FIG. l; and

FIG. 8 is another side elevation view of the tool, partly in section, the tool being folded with the front and rear parts of the tool in the open position.

Referring to the drawings, particularly to FIG. l, the tool comprises a front portion 1 and a rear portion 2 foldably or divisibly connected to the front portion by a hinge pin 3. The latter portion 2 has a conventional grip 4 and includes a rear housing 5 connected to or formed integrally with the grip 4. Within the rear housing 5 there is slidably mounted a rear cylinder 6 within which is rotatably mounted on shoulder 6a a guide 7 for a firing pin assembly 8 with an annular space 9 between the cylinder 6 and guide 7.

The firing pin assembly 8 comprises a firing pin 10 carried by a hollow firing pin carrier 11 in which is mounted a ycoil spring 12 rotatably ysupported a-t its rear end by collar 13a rotatably mounted on shoulder 13b in the rear end wall 13 within the rear housing 5 so lthat the firing pin carrier 11 is urged forwardly.. Indicated by the numeral 14 is a tiring pin carrier guide rod extending into the carrier 11 `as shown. A lock piece 15 having a pawl 16 at its end is normally urged upwardly by a leaf spring 17 into engagement with an opening formed in the wall of the firing pin carrier 11 and is slidable against the rear of shoulder 6a.

Within the handle housing 4 and extending into the rear housing 5 there is pivotally mounted at 18 a rocker arm 19 having a hook 20 at its rear upper end and an upward projection 21 at its forward end portion. The rear cylinder `6 has an -opening 22 in which the proje-ction 2l is engageable when the cylinder 6 is retracted. Indicated by the numeral 23 is a conventional trigger pivotally mounted at 24. The upper shoulder of the trigger 23 engages with the lower face of the rocker arm 19 as shown. When the tool is in the inoperative position shown in FIG. l the projection 2.1 is out of engagement with the opening 22 and the hook 20 on the rocker arm 19 is also out of engagement with the pawl 16 so that even if the trigger 23 is pulled the rocking movement of the arm 19 is prevented by its engagement with the rear cylinder 6 and the tiring pin can not be operated. Indicated by the numeral 25 is a spring to urge the rocker arm 19 in the counter-clockwise direction. When the rear cylinder 6 together with the guide 7 and firing pin carrier 11 is moved rearwardly as a unit during firing as will be set forth hereinafter (which is unitary due to the locking member engaging all these members) against the spring 12 the opening 22 and pawl 16 come into a position engageable with the projection 2.1 and hook respectively, so that when the trigger is pulled the rocker arm 19 can be rotated clockwise against the spring 25 with the projection 21 moving into the opening 22 and the hook 20 engaging the pawl 16 and consequently the lock member 15 is pulled downwardly against the spring 17 out of engagement with the opening in the tiring pin carrier 11 with a result that the latter together with the firing pin 10 is driven forwardly by the compressed spring 1.2 to fire a cartridge. According to this a-rrangement, there are provided two safety measures, namely one is the engagement between the opening 22 and projection 2ll and the other is engagement between the hook 2() and pawl 16.

The front portion 1 of the tool comprises a front housing 26 within which is provided a front cylinder 27 which, when the tool is assembled, has the rear end abutting the front end of the rear cylinder 6 as shown in IFIG. 1. An annular projection 28 is formed on the front cylinder 27 Iand a coil spring 2-9 is inserted in an annular space 30 (formed between the front housing 26 and front cylinder 27) and between a ring 31 lixed to housing 26 and the annular projection 28 in order to urge the `front cylinder 27 rearwardly.

Within the front cylinder 27 and rear cylinder 6 there is inserted a long barrel `32 extending forwardly beyond the front housing 26. A cartridge plug 33 is inserted within the barrel 32. The plug 33 has a forward cylindrical or piston holding opening 34 coaxial with the tool axis and a rear cylindrical opening or cartridge chamber 35 communicating with the forward cylindrical opening 34 and inclined rearwardly and upwardly as shown. The rear end face 37 `of the plug 33 is inclined relative to the vertical cross-sectional plane and is normal to the axis of the cartridge chamber 35. The forward end face of the yguide block 7 is also in-clined to conform with the rear end rface of the plug 33. The lower rear end portion of the plug 33 and the lower front end portion of the guide block 7 are cut away to form a space 36 therebetween for receiving an ejector piece 38 in the form of a cam which is pivotally mounted on the hinge pin 3 which is mounted in guide block 7 and plug 33. The cam piece 38 has at its forward top portion an upward projection 39 which .extends between the plug 33 and guide block 7 and into engagement with the rim ed-ge of a cartridge (not shown) in the cartridge chamber 35. The ejector cam piece 38 also has at its rear lower portion a projection 40 which, when the rear portion 2 is pivoted about the hinge pin 3 away from the front portion 1, engages a projection y41 extending downwardly from the cutout portion of the guide block 7 so that the ejector 38 is rotated clockwise about the pin 3 with a result that the projection 39 also rotates clockwise to eject the cartridge out of the chamber 35 `as shown in FIG. 8. When the tool is pivoted back to the original position, the projection 39 is pushed by the lower edge at the front end yface of the guide block 7 into the original portion shown in FIG. 1.

A sub-barrel 43 is connected to the forward end of the main barrel 32 by means of a nut 44 bridging over these two barrel members and threadedly engaged thereon. Within the sub-barrel 43 there is formed a muzzle 45 o-f a reduced `diameter which ts a piston or plunger 46 which comprises a piston stern 47, an enlarged head portion 48 which merged into the stem through an inclined shoulder 49, and a rear extension 50 which is adapted to be received in the piston holding opening 34 in the plug 33. The sub-barrel 43 has at its rear end an inclined shoulder 51 which fits and abuts the shoulder 49 of the piston 47 when the latter is over driven. The nut 44 has a circumferential groove 52 so that when the piston 47 is unduly overdriven and the shoulder 51 is struck by the piston shoulder 49 the nut 44 is broken at lthe weak groove portion 52 by the unduly high shock and the sub-barrel 43 is separated `from the main barrel 32. Therefore, the unduly high shock is prevented from being transmitted to the main barrel 32 and to the other important mechanisms of the tool.

On the enlarged head portion 48 of the piston 46 there are a plurality of annular projections 53 with annular grooves therebetween. These projections 53 slidably engage the inner wall of the barrel 32. Within at least one annular groove (preferably the rearmost one), there is mounted an O-ring or a friction ring spring 54 which serves not only to retain the piston 46 but also to slidably engage the inner wall of the barrel 32 so that the combustion products within the barrel 32 are scraped or wiped away durin-g each driving operation to prevent undesirable accumulation thereof.

The barrel bore 55 is eccentric relative t-o the barrel 32 and within the barrel body and below the barrel bore is a groove 56 extending longitudinally of the barrel 32. The barrel 32 also has in its lower outer wall a groove 57 extending longitudinally of the barrel 32 except along a threaded portion which will be explained in detail hereinafter. A lock member 58 pivotally mounted on front cylinder 27 and is partly exposed through the front housing 26 as shown. A coil spring 59 is arranged between the rear end portion of the member 58 and the front cylinder 27 to urge the lock mem-ber 58 clockwise so that the projection 60 is forced through an opening in the `front cylinder 27 into the groove 57 on the barrel 32 so that the latter is prevented from rotating.

The most important feature of this invention is a novel measure for varying the axial position of the barrel 32 with respect to the plug 33 or cartridge chamber 35. Referring particularly to FIGS. 4 and 6, a rear portion 61 of the barrel 32 has on its circumference a plurality of transversal ridges or projections 62 with spaces 63 therebetween as most clearly shown in FIG. 4. In the embodiment shown there are eighteen ridges 62 in one row. A plurality of such rows (erg. lfour rows in the embodiment shown) is provided. The arcuate space 64 (FIG. 6) between the adjacent rows of ridges should be longer than the arcuate length of similar ridges provided on the interior walls of the front and rear cylinders 27 and `6. In each row of ridges, the space or width 65 between the adjacent ridges 62 should be such as to t a similar ridge on the front cylinder 27 and rear cylinder 6. A ridge 62 in one row is in alignment with the corresponding ridge in the adjacent row.

On the inner wall of the rear portion of the front cylinder 27 there are also rows of ridges 66 corresponding to those on the barrel 27. In the embodiment shown the number of ridges 66 in each row on the -front cylinder 27 is two. Similarly, on the inner wall of the front portion of the rear cylinder 6 are also corresponding rows of ridges 67. In the embodiment shown there are four ridges 67 in each row.

The arrangement is such that in the assembled state, the barrel 32 is engaged with the front cylinder 27 and rear cylinder 6, with the ridges 62 of the barrel being positioned in the spaces formed by the ridges 66, 67 on the front and rear cylinders `as shown in FIGS. 1 and 2. In this way the Lbarrel 32 is xed against axial movement relative to the front cylinder 27 and rear cylinder 6. The barrel 32 is also prevented from rotation by the lock 58 in engagement with the longitudinal groove 57 as mentioned before.

The above structure enables a user to vary the axial position of the barrel 32 with respect to the cartridge cham-ber 35. This is very advantageous in a tool of this kind because the tool is adaptable to various lengths of fastener, studs, pins or the like and is also able to gen erate various explosive powers without the necessity of exchanging the piston and without the use of cartridges having different explosive powers.

In the operative position shown in FIG. 1, the barrel 32 is in a forward somewhat extended position so that there is left a larger space at 34 between the cartridge chamber 35 and the rear end of the piston or plunger 46. Therefore, with a standard cartridge of predetermined power, the force acting on the piston 46 (and hence the stud 69) would be less than the force produced by the same tool in the operative state shown in FIG. 2 wherein the barrel 3.2 is retracted so that the space lbetween the piston end and the cartridge chamber 35 is smaller. It will also be understood that when the barrel 32 is extended as shown in FIG. 1 it can receive a longer stud than in the case where the barrel 32 is retracted -as shown in FIG. 2. The barrel 32 can `be retracted through the space 9 until its rear end abuts the shoulder 70. It is preferred to provide indicator marks 71 on barrel 32 for indicating the `degree of extension or retraction of the barrel 32 so that the operator can adjust the barrel position as he desires.

The operation of the tool including extension or retraction of the barrel 32 is as follows: After driving in the operative position of FIG. l, the housing 26 is pulled forward against the spring 29 and the `front assembly 26, 27, 32 along with the plug 33, block 7 and tiring pin assembly 10, 1.1, 12, 13a and 14, which rotates within shoulders 6a and 13b, is rotated about 45 so that the ridges 62 disengage `from the ridges 67 on the rear cylinder 6. Due to this disengagement, the said front assembly can now be pulled forwardly and the tool is broken open :as shown in FIG. 8. At this time the waste cartridge is automatically ejected by means of the ejector `38 as explained before. If it is desired to vary the explosive power (the force to act on the piston) or to use a different length of stud, the lock 58 is released .and the barrel 32 is rotated about 45 to disengage the same from .the front cylinder 27, so that the barrel 32 can be extended or retracted relative to the front cylinder 27. The extent of the extension or retraction can be checked rby referring to the indicator marks. Then the barrel 32 is reset by rotating it about 45 in order to engage the same with the `front cylinder 27 and is locked in the new position by the lock S8. Then a stud 69 which may have a conventional disc 70 is inserted into the muz- Zle 45. The enlarged head 71 of the stud is received in :a recess 72 formed at the front end of the piston 4o and the latter is retracted within the barrel 32 to la driving position. A cartridge (not shown) is charged into the cartridge chamber 35. Then the tool is pivoted back to the original position and the front assembly 26, 27, 32 is retracted with the rear end of the barrel extending into the space 9, and then rotated about 45 so that the barrel 32 again engages rear cylinder 6 as shown in FIGS. 1 and 2. The tool is now ready for operation. In operation, the muzzle end is placed against the wall into which the stud is to be driven Land the tool is pressed :against the wall so that the projection 21 on the rocker arm 19 will enter the opening 2.2 and the hook 20 will engage with the pawl 16. When the trigger 23 is pulled the firing pin hits the rim of the cartridge to produce an explosion `as described hereinbefore and the stud 69 is driven into the wall.

It will be noted that since the cartridge chamber 35 is inclined the tool cannot be operated effectively with a ball-cartridge because even if the ball-cartridge is charged and tired the ball or bullet will hit the Wall of the opening 34 or barrel 32 and can not be projected effectively for shooting.

What we claim is:

1. An explosively actuated fastener driving tool having a front portion comprising a barrel, a cartridge receiving plug and on which said barrel is slidably mounted and a piston slidable in said barrel, `and a rear portion comprising a tiring mechanism, said plug being coupled to said firing mechanism, said front portion further comprising a front cylindrical member surrounding the barrel and having a plurality of projections projecting inwardly from the inner surface thereof and spaced along the length thereof, said rear portion further comprising a rear cylindrical member surrounding the barrel land having a plurality of projections projecting inwardly from the inner surface thereof and spaced along the length thereo-f at distances corresponding to the spacing of said projections on said front cylindrical member, said barrel having on its outer circumferential wall a plurality of projections which are spaced `therealong at distances corresponding to the spacing of said projections on said front cylindrical member and engageable and disengageable with the projections on the front and rear cylindrical members, whereby the barrel is movable in an axial direction toward or away from the cartridge receiving plug when the projections are disengaged, while the barrel is locked in position against the axial movement when the projections are engaged.

2. An explosively actuated fastener driving tool as claimed in claim 1 in which the barrel further has a longitudinal groove therealon and a lock member on said front portion engageable in said groove to lock the barrel against a rotational movement.

3. An explosively actuated fastener driving tool as claimed in claim 1 further comprising a sub-barrel at the forward end of the barrel having a reduced diameter portion at the free end thereof, and -a nut having a circumferential groove therein and connecting said subabarrel to said 'barrel so that when the piston is driven with an unduly high shock against the reduced diameter portion of the sub-barrel the nut is ybroken at the grooved portion and the shock is prevented from being transmitted to the barrel :and to the structure provided within the tool.

4. An explosively actuated fastener driving tool as claimed in Claim f1 in which the cartridge receiving plug has a cartridge chamber inclined upwardly and rearwardly relative to the longitudinal axis of said plug.

5. An explosively actuated fastener driving tool kas claimed in claim 1 in which the ring mechanism comprises a -ring pin guide block having a front face abutting the rear end face of the cartridge receiving plug, the plug vand guide block being cut away to dene `a space, an ejector cam piece which is pivotally mounted in said space, said front and rear portions being pivoted to each other on the pivoting axis of said cam piece, said cam piece having an upper projection adapted to engage the rim edge of a cartridge .and a lower projection engageable by said guide :block when said front and rear portions are pivoted relative to each other, whereby when the front portion and rear portion are pivoted relative to each other lthe ejector piece `is rotated due to an engagement of the lower projection by the guide block to eject the cartridge out of the cartridge chamber.

`6. An explosively `actuated fastener driving tool as claimed in claim 1 in which the piston has an annular member thereon slidably engaging the inner W-all of the barrel so that t-he barrel bore is cleaned each time the driving tool is operated.

7. An explosively actuated fastener driving tool as claimed in claim 1 and further comprising la trigger and la safety mechanism within the lrear portion of the tool, said safety mechanism comprising a rocker arm operatively engaged with the trigger and having a projection at its upper forward end and a hook at its upper rear end, said rear cylindrical member having an opening therein into which said projection can enter only when the tiring mechanism is in tiring position, and a lock member having `a pawl thereon with which the said hook is engageable for normally locking the -ring mechanism, said hook releasing said pawl only when the said projection enters the said opening upon pulling the trigger.

No references cited.

GRANVILLE Y. CUSTER. IR., Primary Examiner. 

1. AN EXPLOSIVELY ACTUATED FASTENER DRIVING TOOL HAVING A FRONT PORTION COMPRISING A BARREL, A CARTRIDGE RECEIVING PLUG AND ON WHICH SAID BARREL IS SLIDABLY MOUNTED AND A PISTON SLIDABLE IN SAID BARREL, AND A REAR PORTION COMPRISING A FIRING MECHANISM, SAID PLUG BEING COUPLED TO SAID FIRING MECHANISM, SAID FRONT PORTION FURTHER COMPRISING A FRONT CYLINDRICAL MEMBER SURROUNDING THE BARREL AND HAVING A PLURALITY OF PROJECTIONS PROJECTING INWARDLY FROM THE INNER SURFACE THEREOF AND SPACED ALONG THE LENGTH THEREOF, SAID REAR PORTION FURTHER COMPRISING A REAR CYLINDRICAL MEMBER SURROUNDING THE BARREL AND HAVING A PLURALITY OF PROJECTIONS PROJECTIONS INWARDLY FROM THE INNER SURFACE THEREOF AND SPACED ALONG THE LENGTH THEREOF AT DISTANCES CORRESPONDING TO THE SPACING OF SAID 